Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.99: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
EPR spectrum of tetramer CENI — •Oksana Kravchyna1, M. Orendach2, A. Orendachova2, and M. Kajnakova2 — 1B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine,47 Lenin Ave., Kharkov 61103 Ukraine — 2Center of Low Temperature Physics, Faculty of Sciences, P. J.Safarik University, Park Angelinum 9, 04154, Kosice, Slovakia
The results of investigation of EPR spectrum of metal-organic complex CENI are reported. This investigation has been done at frequency 72.8 GHz and in the temperature region from 2 to 40 K. For T > 15 K the EPR spectrum possess features that are typical for a polycrystalline S = 1/2 paramagnet with a slight axial anisotropy of the g-factor. In other words, the spectra is a wide band with a rather narrow peak at H⊥ and a broad shoulder at H|| if DH is small. At low temperatures, the form of main absorption band was changed. The additional peak is raised near shoulder beginning and small absorption low-field "tail" is observed. At the same time, the high field region shifts to higher magnetic field. This unusual behaviour might be associated with the formation of intracluster magnetic correlations that lead to transitions between the energy levels of the tetrameric unit. That is why the eigenvalues En were calculated by using a numerical diagonalization of the matrix Hamiltonian. The matrix of transition for our work frequency was found. According to our calculation additional resonance transition in spectra of tetramer appeared in intermediate fields. The intensity of this transition must increase with decreasing temperature.